This patch adds "submit" inputs and default (text box) inputs, as well
as form elements that can be submitted.
Layout of input elements is implemented via a new LayoutWidget class
that allows you to put an arbitrary GWidget in the layout tree.
At the moment, the DOM node sets the initial size of the LayoutWidget,
and then the positioning is done by the normal layout algorithm.
We also now support submitting a <form method="GET">, which does a full
replacing load with a URL based on the form's action + a query string
built from the name/value of input elements within the submitted form.
This is pretty neat! :^)
Instead of trying to build the host-side code generator helpers right
before we need them in the LibHTML build process, just build them ahead
of time in makeall.sh, like we already do for {IPC,Form}Compiler.
It's no longer possible to build LibHTML on the host machine since it
depends on LibGUI now. This patch gets rid of the dual Makefiles in
LibHTML since we only support Serenity builds anyway.
Also clean the code generator directory before building it.
This is a simple command that can be used to display HTML from a given
file, or from the standard input, in an HtmlView. It replaces the `tho`
(test HTML output) command.
